In this test, there are two names for the server that has international characters in the domain name. The browsers we tested does not show the domain name in UTF8 in the browser when showing the certificate contents, which we think is wrong. If you have a domain with Swedish characters this should be shown – it will be very hard for a user to compare the names otherwise.

Safari 7.1.3 on OS/X complains that the names doesn’t match, while Firefox and Chrome seems to think it matches.

If you write your own client, this kind of domains are translated before being used in DNS or as a HTTPS uri – the DNS only contains ASCII characters. RFC 6281 explains that these names are encoded in the same way in Subject Alt Names in certificates.

If you click through with a browser, the web page will give you more links to test – both with pre-encoded domain names in the URL and with UTF8 links in the HREF tags. The URL with the emoji could not be saved in this WordPress configuration (obviously a problem with my MySQL database).

Safari shows the encoded names, not the actual names. Maybe a good browser should display both variants.

Fork us on Github

All the tests, including keys and certificates, are available on Github.
https://github.com/edvinanet/tls-o-matic
That's also where you will find all the current tests while waiting for us to write documentation here.

What is TLS?

"The TLS protocol provides communications security
over the Internet. The protocol allows client/server applications to communicate in a way that is designed to prevent eavesdropping, tampering, or message forgery."
From RFC 5446 that defines the current TLS - version 1.2. Wikipedia is also a good help in explaining TLS.